Printed wiring board production method and printed wiring board production apparatus

ABSTRACT

A printed wiring board production method that forms a base film and a conductive pattern on the base film by an additive method or a subtractive method, includes a plating process that electroplates the conductive pattern on a surface of the base film, wherein the plating process includes a shield plate arranging process that arranges a shield plate between an anode and a printed wiring board substrate that forms a cathode, and a substrate arranging process that arranges the printed wiring board substrate in a plating tank, and wherein a distance between the shield plate and the printed wiring board substrate is 50 mm or greater and 150 mm or less.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 16/621,447 filed on Dec. 11, 2019, which is a national stageapplication of International Application No. PCT/JP2018/019493 filed onMay 21, 2018, which is based upon and claims priority to Japanese PatentApplication No. 2017-144089, filed on Jul. 26, 2017, and Japanese PatentApplication No. 2017-218616, filed on Nov. 13, 2017, the entire contentsof which are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a printed wiring board productionmethod and a printed wiring board production apparatus.

2. Description of the Related Art

For the purposes of depositing a uniform plated layer, a means forarranging a shield plate on both left and right sides of a printedwiring board substrate (Patent Document 1), and a method that uses amesh-like net having an insulation sheet arranged at positions where theplated layer is thickly deposited, are known. The shield plate or theinsulation sheet (net) is fixed to the printed wiring board substrateusing a jig, or is provided on a jig that holds the printed wiring boardsubstrate within a plating solution storage tank, and a distance to thesubstrate is less than 50 mm in many cases. Such shields are popularlyutilized, because the size, shape, arranging position, or the like ofthe shield plate or the insulation sheet (hereinafter referred to as theshield plate or the like) can be intuitively and easily changed,corrected, or the like according to the shape and size of the printedwiring board substrate, and the shape or the like of conductive patternsthat are formed, and also because a target to be plated and the shieldplate or the like are adjacent to each other, and a high shieldingeffect is obtainable.

In addition, a method that simultaneously plates both surfaces of aplurality of substrates to be plated, has been proposed (Patent Document3). This method performs a test electroplating or a simulation thereof,to optimize an opening shape of the shield plate, a distance between atarget to be plated and the shield plate, and a positional relationshipof the target to be plated and the shield plate, and it is regarded thatthe plated layer thickness can be made uniform.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: Japanese Laid-Open Patent Publication No.    2005-42170-   Patent Document 2: Japanese Laid-Open Patent Publication No.    2008-88522-   Patent Document 3: Japanese Laid-Open Patent Publication No.    2010-95762

SUMMARY OF THE INVENTION

A printed wiring board production method according to one embodiment ofthe present invention forms a base film and a conductive pattern on thebase film by an additive method or a subtractive method, and includes aplating process that electroplates the conductive pattern on a surfaceof the base film, wherein the plating process includes a shield platearranging process that arranges a shield plate between an anode and aprinted wiring board substrate that forms a cathode, and a substratearranging process that arranges the printed wiring board substrate in aplating tank by a jig that holds the printed wiring board substrate, andwherein a distance between the shield plate and the printed wiring boardsubstrate is 50 mm or greater and 150 mm or less.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view illustrating a plating apparatus that isused in a plating process of the printed wiring board production methodaccording to one embodiment of the present invention;

FIG. 2 is a schematic front view illustrating a fixing jig used by theplating apparatus of FIG. 1 ;

FIG. 3 is a schematic front view illustrating a shield plate used by theplating apparatus of FIG. 1 ;

FIG. 4 is a schematic top view illustrating a plating apparatus,different from that of FIG. 1 , and is used in the plating process ofthe printed wiring board production method;

FIG. 5A is a schematic cross sectional view illustrating a printedwiring board substrate after a seed layer depositing process of theprinted wiring board production method using a semi-additive methodaccording to one embodiment of the present invention, and formation of aresist pattern;

FIG. 5B is a schematic cross sectional view illustrating the printedwiring board substrate in a state where a plated layer is depositedafter an energizing process of the printed wiring board productionmethod using the semi-additive method according to one embodiment of thepresent invention, and formation of a resist pattern;

FIG. 5C is a schematic cross sectional view illustrating a state afterremoval of the resist pattern in a conductive pattern forming process ofthe printed wiring board production method using the semi-additivemethod according to one embodiment of the present invention, andformation of a resist pattern;

FIG. 5D is a schematic cross sectional view illustrating the printedwiring board after the conductive pattern forming process of the printedwiring board production method using the semi-additive method accordingto one embodiment of the present invention, and formation of a resistpattern;

FIG. 6 is a schematic side view illustrating a plating apparatusdifferent from those of FIG. 1 and FIG. 4 ;

FIG. 7 is a schematic front view illustrating an anode shield plate usedby the plating apparatus of FIG. 6 ;

FIG. 8 is a schematic side view illustrating a plating apparatusdifferent from those of FIG. 1 , FIG. 4 , and FIG. 6 ;

FIG. 9 is a schematic side view illustrating a plating apparatusdifferent from those of FIG. 1 , FIG. 4 , FIG. 6 , and FIG. 8 ;

FIG. 10 is a schematic front view illustrating a fixing jig differentfrom that of FIG. 2 ;

FIG. 11 is a schematic enlarged front view of a part of a shield member,enlarged within a frame A of FIG. 10 ; and

FIG. 12 is a schematic enlarged front view illustrating a shield memberdifferent from that of FIG. 11 .

DESCRIPTION OF THE EMBODIMENTS

In the field of electronic devices, a printed wiring board is used inmany cases. The printed wiring board includes a conductive patterndeposited on at least one surface of an insulating base film. A printedwiring board substrate includes the base film, and a seed layer (thinconductive layer having a thickness of approximately several nm)deposited on one surface of the base film, for example, and theconductive pattern is obtained by depositing a plated layer on an outersurface of the seed layer of the printed wiring board substrate, andfurthermore patterning the seed layer and the plated layer.

Generally, a plating process of a printed wiring board productionmethod, that deposits a plated layer, is performed by a platingapparatus including a plating solution storage tank that stores aplating solution, an anode that is immersed in the plating solution andarranged to oppose a printed wiring board substrate, and a mechanismthat applies a voltage to the anode and the printed wiring boardsubstrate. The plating apparatus deposits the plated layer by plating anouter surface of a seed layer that is famed as a cathode.

In order to stably exhibit the performance of the printed wiring board,it is important that conductive patterns within the printed wiring boardare uniformly formed, that is, the plated layer is deposited to auniform thickness. On the other hand, due to improved performance andreduced size of the printed wiring board, both the increase of thedensity of the conductive patterns and the improvement of the refinementof the conductive patterns have been considerable, and it is not easy touniformly deposit the plated layer, even by a semi-additive method thatis the mainstream nowadays and is regarded as being an advantageousmethod of forming micro-patterns.

Problem to be Solved by Present Disclosure

The shield adjacent to the substrate, as in the Patent Documents 1, 2,and 3, requires an extremely strict positional relationship of theshield plate or the like and the position of the target to be platedrequiring the shielding, and a workability is not good in that even aslight misalignment of the shield plate or the like, or the printedwiring board substrate, fixed to a jig, may cause rapid deterioration ofthe thickness uniformity of the plated layer.

In addition, according to the method of the Patent Document 3, the testelectroplating or simulation thereof is troublesome to perform, and isnot preferable from a viewpoint of production efficiency. Further,because the target to be plated is arranged between the shield plates,the substrate to be plated and the shield plates may collide when thesubstrate to be plated is set into the plating solution storage tank andwhen the substrate after the plating is extracted from the platingsolution storage tank.

Accordingly, it is one object of the present disclosure to provide aprinted wiring board production method and a printed wiring boardproduction apparatus, which have a good workability and can easilyarrange and replace the printed wiring board substrate, and make theplated layer thickness uniform.

Effects of Present Disclosure

The printed wiring board production method and the printed wiring boardproduction apparatus according to the present disclosure have a goodworkability and can easily arrange and replace the printed wiring boardsubstrate, and make the plated layer thickness uniform.

Description of Embodiments of Present Invention

First, embodiments of the present invention will be presented anddescribed.

The printed wiring board production method according to one embodimentof the present invention, is a printed wiring board production methodthat forms a base film, and a conductive pattern on the base film, by anadditive method or a subtractive method, and includes a plating processthat electroplates the conductive pattern on a surface of the base film,wherein the plating process includes a shield plate arranging processthat arranges a shield plate between an anode and a printed wiring boardsubstrate forming a cathode, and a substrate arranging process thatarranges the printed wiring board substrate in a plating solutionstorage tank by a jig for holding the printed wiring board substrate,and wherein a distance between the shield plate and the printed wiringboard substrate is 50 mm or greater and 150 mm or less.

The plating process of the printed wiring board production methodarranges the printed wiring board substrate, having the base film and aseed layer deposited on at least one of the surfaces of the base film,so that an outer surface of the seed layer opposes the anode, andsupplies a current to the anode from a voltage applying mechanism whichapplies a voltage, to reduce metal ions dissolved within the platingsolution on the outer surface of the seed layer forming the cathode, anddeposit the plated layer on the outer surface of the seed layer. In thisprinted wiring board production method, by arranging the shield platebetween the anode and the printed wiring board substrate, at thedistance of 50 mm or greater and 150 mm or less from the printed wiringboard substrate, an appropriate current distribution is obtained withinthe plating solution, and the metal ions can be uniformly reduced on theouter surface of the seed layer forming the cathode, to make the platedlayer thickness uniform. In addition, by setting the distance betweenthe shield plate and the printed wiring board substrate to fall withinthe above-mentioned range, the arrangement and replacement operation ofthe printed wiring board substrate in the plating solution storage tankare simplified, and the production efficiency of the printed wiringboard is improved.

The above-mentioned jig preferably includes a shield member. When theplating process is performed in a state where the printed wiring boardsubstrate is misaligned in a horizontal direction within the platingsolution storage tank, that is, misaligned along a width direction ofthe printed wiring board substrate, the plated layer thickness may varynear an end part along the width direction of the printed wiring boardsubstrate. In this printed wiring board production method, the jig thatholds the printed wiring board substrate within the plating solutionstorage tank includes the shield member, and thus, the currentdistribution near the end part along the width direction of the printedwiring board substrate can be set appropriately. Hence, even when theplating process is performed in the state where the printed wiring boardsubstrate is misaligned in the horizontal direction within the platingsolution storage tank, it is possible to make the plated layer thicknessuniform in the printed wiring board substrate.

The above-mentioned shield member is preferably arranged at an endregion along at least the width direction of the printed wiring boardsubstrate in a plan view. When the shield member covers the end regionalong at least the width direction of the printed wiring board substratein the plan view, it is possible to appropriately set the currentdistribution near the end part along the width direction of the printedwiring board substrate.

The shield member preferably includes shield member openings. When theshield member includes the shield member openings, it is possible tomore appropriately set the current distribution near the end part alongthe width direction of the printed wiring board substrate within theplating solution, and the plated layer thickness can be made even moreuniform near the end part of the printed wiring board substrate.

An opening ratio of the above-mentioned shield member is preferably 20%or higher and 80% or lower. When the opening ratio of the shield memberis 20% or higher and 80% or lower, it is possible to more appropriatelyset the current distribution near the end part along the width directionof the printed wiring board substrate, and the plated layer thicknesscan be made even more uniform near the end part of the printed wiringboard substrate.

The above-mentioned shield plate preferably includes shield plateopenings. When the shield plate includes the shield plate openings, thecurrent distribution is more appropriately set within the platingsolution, and the plated layer thickness can be made even more uniform.

Preferably, the shield plate openings are formed at an opening region ofthe shield plate, the opening region is a region opposing the printedwiring board substrate in the plan view, and an opening ratio of acentral opening region of the above-mentioned opening region is 10% orhigher and 50% or lower, and an opening ratio of an end opening regionof the above-mentioned opening region is higher than the opening ratioof the central opening region. When the shield plate openings are notformed at a part larger than an external size of the printed wiringboard substrate, and are formed in the region opposing the printedwiring board substrate, it is possible to effectively reduceconcentration of the current distribution near an outer peripheral endpart of the printed wiring board substrate. In addition, when theopening ratio of the central opening region is 10% or higher and 50% orlower, and the opening ratio at the end of the opening region is sethigher than the opening ratio of the central opening region, the platedlayer thickness of the printed wiring board substrate can be made evenmore uniform.

The external size of the above-mentioned shield plate is preferablygreater than the external size of the printed wiring board substrate inthe plan view. Generally, the plated layer thickness near the outerperipheral end part of the printed wiring board substrate tends tobecome thick. But when the external size of the shield plate is greaterthan the external size of the printed wiring board substrate in the planview, it is possible to prevent the current distribution fromconcentrating near the outer peripheral end part of the printed wiringboard substrate, and reduce the increase of the plated layer thicknessnear the outer peripheral end part.

An anode shield plate is preferably arranged between the above-mentionedshield plate and the anode. By further arranging the anode shield plate,the current distribution can be made uniform near the anode, andcombined with the effects of the shield plate, it is possible to makethe plated layer thickness even more uniform.

The anode shield plate preferably includes anode shield plate openings.Because the anode shield plate includes the anode shield plate openings,an exposure area (effective area) of the anode with respect to theprinted wiring board substrate can be appropriately adjusted, to makethe current distribution even more uniform near the anode, and combinedwith the effects of the shield plate, it is possible to make the platedlayer thickness even more uniform.

An area of the anode shield plate (an area of the anode shield plateincluding the anode shield plate openings in a case where the anodeshield plate includes the anode shield plate openings) in theabove-mentioned plating process is preferably greater than an immersionarea of the anode into the plating solution. By making the immersionarea of the anode shield plate into the plating solution greater thanthe immersion area of the anode into the plating solution, it ispossible to further reduce the increase of the plated layer thicknessnear the outer peripheral end part of the printed wiring boardsubstrate.

Preferably, the thickness of the plated layer formed as theabove-mentioned conductive pattern is 30 μm or greater, and aninconsistency of the thickness is within 15% of an average thickness ofthe plated layer. Generally, the greater the plated layer thicknessbecomes, there is a tendency for the inconsistency of the plated layerthickness to increase. When the plated layer thickness of the conductivepattern of the printed wiring board is 30 μm or greater, and theinconsistency of the thickness is within 15% of the average thickness ofthe plated layer, it is possible to stabilize the performance of aproduct device using the printed wiring board.

The above-mentioned conductive pattern is preferably deposited by thesemi-additive method. It is not easy to uniformly deposit the platedlayer, even by the semi-additive method that is the mainstream nowadaysand is regarded as being the advantageous method of formingmicro-patterns. But according to the printed wiring board productionmethod of the embodiment, a complicated shield structure, accurate andrigid fixing of the shield plate, or the like are not required, and asatisfactory effect of making the plated layer thickness uniform can beexhibited by a simple arrangement of the shield plate using thesemi-additive method.

The printed wiring board production apparatus according to anotherembodiment of the present invention, is a printed wiring boardproduction apparatus that forms a base film, and a conductive pattern onthe base film, by the additive method or the subtractive method, andincludes a plating solution storage tank, a substrate fixing mechanismthat fixes the printed wiring board substrate that is the target to beplated, an anode arranged to oppose the printed wiring board substrate,a shield plate arranged between the printed wiring board substrate andthe anode, and a voltage applying mechanism that applies a voltage tothe anode, and the printed wiring board substrate forming a cathode,wherein a distance between the shield plate and the printed wiring boardsubstrate is 50 mm or greater and 150 mm or less.

The printed wiring board production apparatus arranges the printedwiring board substrate, having the base film and a seed layer depositedon at least one of the surfaces of the base film, so that an outersurface of the seed layer opposes the anode. The printed wiring boardproduction apparatus supplies a current to the anode from the voltageapplying mechanism which applies the voltage, to reduce metal ionsdissolved within the plating solution on the outer surface of the seedlayer forming the cathode, and deposit the plated layer on the outersurface of the seed layer. In this printed wiring board productionapparatus, by arranging the shield plate between the anode and theprinted wiring board substrate, at the distance of 50 mm or greater and150 mm or less from the printed wiring board substrate, an appropriatecurrent distribution is obtained within the plating solution, and themetal ions can be uniformly reduced on the outer surface of the seedlayer forming the cathode, to make the plated layer thickness uniform.

The plating solution storage tank preferably includes a shield platefixing mechanism that fixes the above-mentioned shield plate. When theplating solution storage tank includes the shield plate fixing mechanismthat fixes the shield plate, the shield plate can be arranged and fixedwith ease. When the shape or size of the printed wiring board substrate,or the structure of the conductive pattern that is formed changes, it ispossible to easily cope with the change by replacing the shield plate byan optimum shield plate that is selected in the shield plate fixingmechanism.

Details of Embodiments of Present Invention

Next, the printed wiring board production method and the printed wiringboard production apparatus according to the embodiment of the presentinvention will be described by referring to the drawings, asappropriate.

First Embodiment

<Printed Wiring Board Production Method>

The printed wiring board production method according to one embodimentof the present invention includes a plating process that electroplates aconductive pattern on a surface of a base film. This plating process isperformed by a plating apparatus 1 including a plating solution storagetank 2 that stores a plating solution Y, a fixing jig 3 that fixes aprinted wiring board substrate X forming a cathode and immersed in theplating solution Y, an anode 6 immersed in the plating solution Y andarranged to oppose the printed wiring board substrate X, and a mechanism7 (hereinafter also referred to as a “voltage applying mechanism 7”)that applies a voltage to the anode 6 and the printed wiring boardsubstrate X, as illustrated in FIG. 1 , for example. First, the platingapparatus 1 will be described before describing the plating process. Inthe following description, “up” refers to a direction of an opening ofthe plating solution storage tank 2, “down” refers to a direction of abottom of the plating solution storage tank 2, “front and rear” refersto a direction along a long side of the bottom of the plating solutionstorage tank 2, and “left and right” refers to a direction along a shortside of the bottom of the plating ink tank 2.

[Plating Apparatus]

The plating apparatus 1 is used in a state where the printed wiringboard substrate X, including the base film and the seed layer depositedon one of the surfaces of the base film, is arranged so that the outersurface of the seed layer opposes an opposing surface of the anode 6,for example. The plating apparatus 1 supplies the current to the anode 6from the voltage applying mechanism 7, and can reduce the metal ionsdissolved within the plating solution Y on the outer surface of the seedlayer forming the cathode, to deposit the plated layer on the outersurface of the seed layer. In this plating apparatus 1, a shield plate 9is arranged between the anode 6 and the printed wiring board substrateX, and the distance between the printed wiring board substrate X and theshield plate 9 is set to 50 mm or greater and 150 mm or less, so thatthe appropriate current distribution is obtained within the platingsolution Y, and the metal ions are uniformly reduced on the outersurface of the seed layer, to make the plated layer thickness uniform.

(Anode)

The anode 6 has a constant thickness and a plate shape. In addition, theanode 6 is formed to a rectangular shape in a front view from theprinted wiring board substrate X. A “front view from A” refers to astate visible when viewed from A. In other words, a “front view from theprinted wiring board substrate X, or the anode 6” refers to a visiblestate when viewed from the printed wiring board substrate X or the anode6.

The external size of the anode 6 in the state immersed in the platingsolution Y is not particularly limited, but a lower limit value of anaverage length along the up and down direction is preferably 200 mm, andmore preferably 500 mm. An upper limit value of the average length alongthe up and down direction is preferably 1000 mm, and more preferably 800mm. A lower limit value of the average length along the horizontaldirection is preferably 200 mm, and more preferably 450 mm. An upperlimit value of the average length along the horizontal direction ispreferably 1000 mm, and more preferably 750 mm. When the average lengthsalong the up and down direction and the horizontal direction do notreach the respective lower limits, it may not be possible to obtain asufficient production efficiency of the printed wiring board. When theaverage lengths along the up and down direction and the horizontaldirection exceed the respective upper limits, it may become difficult tocontrol the plated layer thickness deposited on the printed wiring boardsubstrate X. Generally, the anode 6 contracts when immersed in theplating solution Y. For this reason, in a state not immersed in theplating solution Y, the average length of the anode 6 along the up anddown direction may be approximately 400 mm or greater and approximately1200 mm or less, for example, and the average length along thehorizontal direction may be approximately 300 mm or greater andapproximately 1000 mm or less, for example.

The distance between the anode 6 and the printed wiring board substrateX is not particularly limited, but a lower limit is preferably 100 mm,and more preferably 125 mm. In addition, an upper limit of the distanceis preferably 300 mm, and more preferably 250 mm. When the distance doesnot reach the lower limit, it may become difficult to uniformly depositthe plated layer on the printed wiring board substrate X. When thedistance exceeds the upper limit, it may become difficult to control theplated layer thickness deposited on the printed wiring board substrateX.

A current density of the anode 6 is not particularly limited, but alower limit is preferably 1.0 ASD (0.01 A/m²), and more preferably 1.2ASD (0.012 A/m²). In addition, an upper limit of the current density ispreferably 4.5 ASD (0.045 A/m²), and more preferably 3.0 ASD (0.03A/m²). When the current density of the anode 6 does not reach the lowerlimit, it may not be possible to obtain a sufficient productionefficiency of the plated layer deposited on the printed wiring boardsubstrate X. When the current density of the anode 6 exceeds the upperlimit, it may become difficult to control the plated layer thicknessdeposited on the printed wiring board substrate X.

The anode 6 is not particularly limited, and for example, known anodesincluding a soluble anode, an insoluble anode, or the like, may be usedtherefor. The soluble anode may have a metal such as copper, nickel,silver, or the like as a main component thereof, and the insoluble anodemay use platinum, iridium-coated titanium, or the like. Among suchanodes, the insoluble anode is preferable in that a change in the shapeof the anode itself can be prevented, and the plated layer thickness canbe uniformly deposited with ease on the printed wiring board substrateX.

(Fixing Jig)

The fixing jig 3 includes a frame 4 that includes an opening and holdsan outer periphery of the printed wiring board substrate X, and a pairof arms 5 extending upward from the frame 4, as illustrated in FIG. 2 .The pair of arms 5 engages bars (not illustrated) suspended above aliquid surface of the plating solution Y, and suspends the frame 4, andthe printed wiring board substrate X held by the frame 4, within theplating solution Y.

The frame 4 includes an inner edge and an outer edge forming arectangular frame body, and holds the printed wiring board substrate Xat the opening thereof. In other words, the frame 4 holds the printedwiring board substrate X so as to cover the outer periphery of theprinted wiring board substrate X. As an example, the frame 4 that holdsthe entire outer periphery of the printed wiring board substrate X willbe described, however, the frame 4 is not limited to such, and knownframes, including a frame that holds two sides of the printed wiringboard substrate X, such as the left and right sides in FIG. 2 , forexample, a frame that holds one side of the printed wiring boardsubstrate X, such as only the top side in FIG. 2 , for example, or thelike, may be used therefor. Similarly, the arms 5 are not limited tothat famed by the pair, and known arms, such as that formed by a singlearm, or the like, may be used therefor.

The substrate X for the printed wiring board, held by the frame 4,includes the insulating base film, and the conductive seed layerdeposited on one surface of the base film, and is arranged within theplating solution Y so that the seed layer opposes the anode 6.

(Voltage Applying Mechanism)

The voltage applying mechanism 7 includes a power supply 8 that suppliesa current to the anode 6. In addition, the voltage applying mechanism 7includes a first interconnection part that electrically connects thepower supply 8 and the anode 6, and a second interconnection part thatelectrically connects the power supply 8 and the seed layer of theprinted wiring board substrate X held by the fixing jig 3. Theelectrical connection to the seed layer and the second interconnectionpart may be provided on the fixing jig 3, or provided independently ofthe fixing jig 3.

(Plating Solution)

The plating solution Y is not particularly limited, but known platingsolutions including copper sulfate, copper pyrophosphate, or the like,for example, may be used therefor.

(Shield Plate)

The shield plate 9 has a constant thickness and a plate shape. The shapeof the shield plate 9 is not particularly limited, but the shield plate9 preferably has a rectangular shape in the plan view when the printedwiring board substrate X, that is the target to be plated, has arectangular shape in the plan view.

A material used for the shield plate 9 is not particularly limited, aslong as the material is an insulator that has plating resistance, andfor example, known materials including vinyl chloride,polytetrafluoroethylene, or the like, may be used therefor.

The shield plate 9 is arranged between the anode 6 and the printedwiring board substrate X. More particularly, the shield plate 9 isarranged parallel to the anode 6 and the printed wiring board substrateX, and overlaps the printed wiring board substrate X in a front viewfrom the anode 6. In the plating solution Y, a distribution of thecurrent flowing from the anode 6 to the seed layer of the printed wiringboard substrate X forming the cathode, becomes dense near the outerperipheral end part of the printed wiring board substrate X, and theplating layer becomes thick thereat. In addition, even at parts otherthan the outer peripheral end part of the printed wiring board substrateX, the current distribution becomes sparse at parts where the seed layerthat becomes the conductive pattern is exposed (hereinafter alsoreferred to as the exposed seed layer) is densely provided, and thecurrent distribution becomes dense at parts where the exposed seed layeris sparsely provided, to thereby generate inconsistencies in the platedlayer thickness. Further, depending on individuality based on thespecific configuration or the like of the apparatus, it may be difficultto obtain a uniform current distribution. The shield plate 9 is arrangedto make uniform the current distribution that may become sparse ordense. In other words, it is possible to uniformly deposit the platedlayer by arranging the shield plate 9. “Parallel” referred above notonly includes a perfectly parallel state, but also includes states wherean inclination is within 5 degrees. Moreover, “the shield plate 9 thatoverlaps the printed wiring board substrate X in the front view from theanode 6” referred above includes a state where the printed wiring boardsubstrate X is concealed by the shield plate 9 in the front view fromthe anode 6 when the external size of the shield plate 9 is larger thanthe external size of the printed wiring board substrate X, and a statewhere the shield plate 9 falls within a range of the printed wiringboard substrate X in the front view from the anode 6 when the externalsize of the shield plate 9 is the same as or smaller than the externalsize of the printed wiring board substrate X.

A lower limit value of the distance between the shield plate 9 and theprinted wiring board substrate X is 50 mm, preferably 60 mm, and morepreferably 70 mm. An upper limit value of the above-mentioned distanceis 150 mm, preferably 140 mm, and more preferably 130 mm. When theabove-mentioned distance does not reach the above lower limit, thedistance for making the current distribution sufficiently uniform cannotbe obtained, and it may not be possible to deposit the plated layer to auniform thickness in a case where the printed wiring board substrate Xis warped, or the printed wiring board substrate X is fixed to thefixing jig 3 at a position deviated from a normal fixing position. Whenthe above-mentioned distance exceeds the above upper limit, the currentdistribution that is once made uniform may lose the uniformalizingeffect of the shield plate 9 before the printed wiring board substrate Xis reached, and it may not be possible to deposit the plated layer to auniform thickness. The “distance between the shield plate 9 and theprinted wiring board substrate X” refers to the distance between acenter of the surface of the printed wiring board substrate X having theexposed seed layer, and a center of the surface of the shield plate 9opposing the printed wiring board substrate X.

The external size of the shield plate 9 that is famed to the rectangularshape is not particularly limited, but the external size of the shieldplate 9 is preferably larger than the external size of the printedwiring board substrate X. For example, a lower limit value of the lengthalong the up and down direction may be 400 mm, and preferably 550 mm. Anupper limit value of the length along the up and down direction may be1300 mm, and preferably 850 mm. A lower limit value of the length alongthe horizontal direction may be 400 mm, and preferably 500 mm. An upperlimit value of the length along the horizontal direction may be 1100 mmor less, and preferably 800 mm. By making the external size of theshield plate 9 larger than the external size of the printed wiring boardsubstrate X, it is possible to prevent the current distribution fromconcentrating near the outer peripheral end part of the printed wiringboard substrate X.

In addition, the shield plate 9 preferably includes shield plateopenings 10, as illustrated in FIG. 3 . Because the shield plate 9includes the shield plate openings 10, it is possible to moreappropriately control the current distribution. The shape and theexternal size of the shield plate 9, and the shape, size, number, or thelike of the shield plate openings 10, may be selected to become optimum,as appropriate, according to the individuality based on the specificconfiguration or the like of the plating apparatus 1, the external sizeof the printed wiring board substrate X, the structure of the exposedseed layer, or the like.

The shield plate openings 10 are preferably formed in an opening region11 that is a region opposing the printed wiring board substrate X. Byproviding the plurality of shield plate openings 10 within the region ofthe shield plate 9 opposing the printed wiring board substrate X, thatis, within the region at the part of the shield plate 9 overlapping theprinted wiring board substrate X in the front view from the anode 6, itis possible to appropriately control the current distribution. Further,by not providing the openings in the part of the shield plate 9exceeding the external size of the printed wiring board substrate X,that is, in the region at the part of the shield plate 9 exceeding theexternal size of the printed wiring board substrate X (the region of theshield plate 9 not opposing the printed wiring board substrate X) in thefront view from the anode 6, it is possible to effectively reduce theconcentration of the current distribution near the outer peripheral endpart of the printed wiring board substrate X.

The opening ratio of the shield plate openings 10 in the opening region11 is preferably varied between a central opening region 12 that is aregion at an approximate center of the opening region 11, and an endopening region 13 that is a region other than the central opening region12. More particularly, a lower limit value of the opening ratio of thecentral opening region 12 may be 10%, preferably 15%, and morepreferably 20%. An upper limit value of the opening ratio of the centralopening region 12 may be 50%, preferably 45%, and more preferably 40%.When the opening ratio of the central opening region 12 does not reachthe above lower limit, it may not be possible to deposit the platedlayer to a desired thickness. When the opening ratio of the centralopening region 12 exceeds the above upper limit, the plated layer maythicken and make contact with an adjacent plated layer.

In addition, as illustrated in FIG. 3 , the opening ratio of the endopening region 13 is preferably higher than the opening ratio of thecentral opening region 12. By making the opening ratio of the endopening region 13 higher than the opening ratio of the central openingregion 12, the current distribution with respect to the entire surfaceof the printed wiring board substrate X can be controlled moreprecisely, to make the plated layer thickness uniform. Moreparticularly, the opening ratio of the end opening region 13 may behigher than the opening ratio of the central opening 12 by 1%,preferably 2%, and more preferably 3%. In other words, a lower limitvalue of (opening ratio of end opening region 13/opening ratio ofcentral opening region 12)×100(%) may be 101%, preferably 102%, and morepreferably 103%. An upper limit value of (opening ratio of end openingregion 13/opening ratio of central opening region 12)×100(%) may be110%, preferably 109%, and more preferably 108%. Because the shieldplate openings 10 are not provided at the part on the outer side of theend opening region 13, that is, at the part of the shield plate 9exceeding the external size of the printed wiring board substrate X, itis possible to reduce the concentration of the current distribution atthe outer peripheral end of the printed wiring board substrate X.However, when the opening ratio of the opening region 11 is constant, ordoes not reach the above lower limit, the formation of the plated layeris promoted at a central part of the printed wiring board substrate X,while the formation of the plated layer is reduced at the peripheralpart other than the central part of the printed wiring board substrateX, due to the above-mentioned reducing effect, and it may becomedifficult to make the plated layer thickness uniform. When the aboveupper limit is exceeded, the above-mentioned reducing effectdeteriorates, and the formation of the plated layer is promoted at theouter peripheral end part of the printed wiring board substrate X, whilethe formation of the plated layer is reduced at the central part of theprinted wiring board substrate X, and it may become difficult to makethe plated layer thickness uniform. The opening ratio of the centralopening region or the end opening region of the shield plate refers to aratio of the area of the central opening region or the end openingregion (each including the shield plate openings) with respect to thearea of the shield plate openings.

The size or the like of the central opening region 12 within the openingregion 11 may be adjusted, as appropriate, according to the structure ofthe exposed seed layer of the printed wiring board substrate X, the arearatio of the printed wiring board substrate X and the shield plate 9 inthe plan view, or the like, and is not particularly limited. Whenproviding the end opening region 13 at upper and lower ends of theopening region 11, the central opening region 12 may be a region that is10% or more and 90% or less, preferably 15% or more and 85% or less, andmore preferably 20% or more and 80% or less from the upper end of theopening region 11 in FIG. 3 , for example. When the region that is 10%or more and 90% or less from the upper end of the opening region 11 isthe central opening region 12, the end opening region 13 may be a regionlocated less than 10% from the upper end of the opening region 11, and aregion located more than 90% from the upper end and reaching the lowerend of the opening region 11.

In addition, the end opening region 13 may be provided at left and rightends, or at the upper and lower ends and the left and right ends of theopening region 11, according to the configuration, shape, or the like ofthe frame 4 that holds the printed wiring board substrate X, or the jig.

When providing the end opening region 13 at the left and right ends ofthe opening region 11, the central opening region 13 may be a regionthat is 10% or more and 90% or less, preferably 15% or more and 85% orless, and more preferably 20% or more and 80% or less from the left endof the opening region 11 in FIG. 3 , for example. When the region thatis 10% or more and 90% or less from the left end of the opening region11 is the central opening region 12, the end opening region 13 may be aregion located less than 10% from the left end of the opening region 11,and a region located more than 90% from the left end and reaching theright end of the opening region 11.

When providing the end opening region 13 at the upper and lower ends andthe left and right ends of the opening region 11, the central openingregion 13 may be a region that is 10% or more and 90% or less from theupper end of the opening region 11, and is 10% or more and 90% or lessfrom the left end of the opening region 11 in FIG. 3 , for example. Inthis case, a region located less than 10% from the upper end of theopening region 11 and a region located more than 90% from the upper endand reaching the lower end of the opening region 11, and a regionlocated less than 10% from the left end of the opening region 11 and aregion located more than 90% from the left and reaching the right end ofthe opening region 11, may become the end opening region 13. The centralopening region 13 is preferably a region that is 15% or more and 85% orless from the upper end of the opening region 11, and 15% or more and85% or less from the left end of the opening region 11, and morepreferably a region that is 20% or more and 80% or less from the upperend of the opening region 11, and 20% or more and 80% or less from theleft end of the opening region 11.

The shield plate openings 10 are not limited to a particular shape, anda circular hole, a rectangular hole, a diamond-shaped hole, or the likemay be used therefor. In addition, the variation in the opening ratio ofthe end opening region 13 with respect to the central opening region 12is not particularly limited, and may be a variation due to differentopening areas with the same opening shape, a variation due to differentopening shapes, a variation due to the number per unit area with thesame opening shape and the shape opening area, or the like.

The plating solution storage tank 2 preferably includes a shield platefixing mechanism that fixes the shield plate 9. By providing the shieldplate fixing mechanism, it becomes possible to easily arrange and fixthe shield plate 9. In addition, even when a modification is made to theshape, the external size, the structure of the exposed seed layer, orthe like of the printed wiring board substrate X, it is possible toeasily cope with the modified printed wiring board substrate, byselecting the shield plate having the optimum shape, external size, andshield plate openings for the modified printed wiring board substrate,and fixing the selected shield plate to the shield plate fixingmechanism.

The means for fixing the shield plate 9 is not particularly limited, andas illustrated in FIG. 4 , for example, fixing slits 14 that hold theshield plate 9 may be provided on an inner side of left and right (upperand lower in FIG. 4 ) sidewalls of the plating solution storage tank 2,to extend from an upper surface toward a bottom wall of the platingsolution storage tank 2. 1 set is formed by the fixing slits 14 that areprovided on the inner side of the left and right sidewalls of theplating solution storage tank 2 to oppose each other, and a plurality ofsets are preferably provided. By providing the plurality of sets of thefixing slits 14, it becomes possible to easily move the shield plate 9to a distance where the optimum shielding effect is obtained, when theshape or the like of the printed wiring board substrate X is modified.The fixing slits 14 may be integrally famed on the plating solutionstorage tank 2, or may be formed separately and attached to the platingsolution storage tank 2. In the case of the separately formed fixingslits, one set of fixing slits may include a mechanism or the like thatenables the fixing slits and the shield plate 9 held by the fixing slitsto slide toward the front and rear (left and right in FIG. 4 ) and befixed at a predetermined position within the plating solution storagetank 2.

(Plating Process)

Next, a state where the plated layer is deposited on the outer surfaceof the exposed seed layer of the printed wiring board substrate, and theconductive pattern is famed, in the plating process of the printedwiring board production method, will be described. The printed wiringboard production method may employ either the additive method or thesubtractive method. The additive method includes a full additive methodand a semi-additive method. As an example, the plating process using thesemi-additive method will be described, by referring to FIG. 5A throughFIG. 5D.

(Method Using Semi-Additive Method)

The plating process of this printed wiring board production methodincludes a seed layer depositing process, a resist pattern formingprocess, an energizing process, and a conductive pattern forming method.

(Seed Layer Depositing Process)

In the seed layer depositing process, a conductive seed layer 16 isdeposited on one surface of an insulating base film 15, as illustratedin FIG. 5A. The main component of the base film 15 includes a syntheticresin such as polyimide, polyethylene terephthalate, or the like, forexample. The method of depositing the seed layer 16 is not particularlylimited, and known methods including electroless plating, vapordeposition, sputtering, or the like, for example, may be employed. Inaddition, the main component of the seed layer 16 includes nickel, gold,silver, tungsten, molybdenum, copper, cobalt, chromium, iron, zinc, orthe like, and among these elements, copper is preferable from aviewpoint of providing strong adhesion to the base film 15 and asuitable surface for starting the plating. The “main component” refersto a component having a largest content, and includes a component havinga content that is 50 mass % or greater, for example.

A lower limit of an average thickness of the seed layer 16 may be 10 nm,preferably 50 nm, and more preferably 100 nm. An upper limit of theaverage thickness of the seed layer 16 may be 1 μm, preferably 700 nm,and more preferably 500 nm. When the average thickness of the seed layer16 does not reach the above-mentioned lower limit, a discontinuity maybe generated in the seed layer 16 in the plan view, to make it difficultto deposit the plated layer to a uniform thickness on an outer surfaceof the seed layer 16. When the average thickness of the seed layerexceeds the above-mentioned upper limit, the production efficiency maydeteriorate.

(Resist Pattern Forming Process)

In the resist pattern forming process, a resist pattern Z is formed onthe outer surface of the seed layer 16 that is deposited by the seedlayer depositing process, as illustrated in FIG. 5A. More particularly,in the resist pattern forming process, a photosensitive resist is firstdeposited on the outer surface of the seed layer 16. Next, a patterningcorresponding to the conductive pattern is performed with respect to theresist, by exposing, developing, or the like, to form the resist patternZ.

(Energizing Process)

In the energizing process, the voltage applying mechanism 7 supplies acurrent to the anode 6 and the printed wiring board substrate X. By thisenergizing process, a plated layer 17 is deposited on the seed layer 16having no resist pattern Z deposited thereon, that is, on the outersurface of the exposed seed layer, as illustrated in FIG. 5B.

The main component of the plated layer 17 that is deposited in theenergizing process includes copper, nickel, silver, or the like. Amongthese elements, copper is preferable because of the good conductivityand the ease with which the plated layer 17 having a uniform thicknesscan be famed at a relatively low cost.

An average thickness of the plated layer 17 that is deposited in theenergizing process is preferably 30 μm or greater. In addition,thickness inconsistencies of the plated layer 17, that is, a differencebetween the average thickness and a maximum thickness, and a differencebetween the average thickness and a minimum thickness, are preferably15% or less, respectively. When the plated layer thickness of theconductive pattern of the printed wiring board is 30 lam or greater, andthe inconsistency of the thickness is within 15% of the averagethickness of the plated layer, it is possible to stabilize theperformance of the product device using the printed wiring board withsuch plated layer thickness. The difference between the averagethickness and each of the maximum thickness and the minimum thickness ofthe plated layer 17 is preferably as small as possible, and a lowerlimit of this difference may be 0%. The plated layer thickness and theinconsistency thereof do not include the part of the plated layerthickness not forming the product, and need only be managed for theprinted wiring board that becomes the product. More particularly, anon-product part including a predetermined range from the outer edge ofthe printed wiring board substrate X, such as a part where the frame 4(FIG. 2 ) holds the printed wiring board substrate X, or the like, isnot included the target to be managed of the plated layer thickness.

(Conductive Pattern Forming Process)

In the conductive pattern forming process, a conductive pattern 18 isformed on one surface of the base film 15, as illustrated in FIG. 5D.More particularly, in the conductive pattern forming process, the resistpattern Z is first removed, as illustrated in FIG. 5C, and a regionwhere the resist pattern Z was deposited on the seed layer 16 is nextremoved by an etching or the like, as illustrated in FIG. 5D.

[Advantages]

By setting the distance between the printed wiring board substrate X andthe shield plate 9 to 50 mm or greater and 150 mm or less in the platingprocess, and optimizing the shape or the like of the shield plate 9,this printed wiring board production method can deposit the plated layerhaving the thickness that is uniform to the same extent as or moreuniform than that obtained by the method that arranges a shield elementadjacent to the printed wiring board substrate. In addition, because theprinted wiring board substrate X and the shield plate 9 are separated,it is possible to easily and quickly perform operations of arranging andreplacing the printed wiring board substrate X and the shield plate 9.Further, in the case of the method that arranges the shield elementadjacent to the printed wiring board substrate, rigid fixing of theshield element is required to prevent the precise positioning of theshield element with respect to the printed wiring board substrate, andthe positional relationship of the printed wiring board substrate andthe shield element, from deviating due to vibration or the like duringthe plating process. On the other hand, because the shield plate 9 thatis separated from the printed wiring board substrate X can appropriatelycontrol the current distribution within the plating solution Y in thedisclosed printed wiring board production method, it is possible todeposit the plated layer having the uniform thickness, even when aslight error is generated in the positional relationship of the shieldplate 9 and the printed wiring board substrate X. Hence, the operationsof arranging and replacing the printed wiring board substrate X and theshield plate 9 can be performed in an extremely simple manner.Accordingly, it is possible to improve the production efficiency of theprinted wiring board having the conductive pattern that is formed by theplated layer having the uniform thickness.

Second Embodiment

<Printed Wiring Board Production Method>

The printed wiring board production method according to anotherembodiment of the present invention will be described, by referring toFIG. 6 . In this embodiment, constituent parts that are the same asthose of the first embodiment will be designated by the same referencenumerals, and a description thereof will be omitted.

The plating process of this printed wiring board production methoddeposits, by the plating apparatus 1, the plated layer on the outersurface of the exposed seed layer of the printed wiring board substrateX forming the cathode. In the plating apparatus 1, the shield plate 9 isarranged 50 mm or greater and 150 mm or less from the printed wiringboard substrate X, and an anode shield plate 19 is further arranged, sothat a more appropriate current distribution is obtained within theplating solution Y, the metal ions are more uniformly reduced on theouter surface of the seed layer, and the uniformity of the plated layerthickness is further improved. The plating process of this printedwiring board production method differs from the plating process of theabove-mentioned first embodiment, in that the anode shield plate 19 isprovided, and thus, a description will hereinafter be given mainly onthe anode shield plate 19.

(Anode Shield Plate)

The anode shield plate 19 has a constant thickness and a plate shape.The shape of the anode shield plate 19 is not particularly limited, butwhen the shape of the anode 6 is rectangular in the plan view, the shapeof the anode shield plate 19 in the plan view is preferably rectangular.

A material used for the anode shield plate 19 is not particularlylimited, as long as the material is an insulator that has platingresistance, similar to the shield plate 9.

The anode shield plate 19 is arranged between the anode 6 and the shieldplate 9. More particularly, the anode shield plate 19 is arrangedparallel to the anode 6, and overlaps the shield plate 9 in the frontview from the printed wiring board substrate X. In the plating solutionY, the distribution of the current flowing from the anode 6 to theexposed seed layer of the printed wiring board substrate X forming thecathode, becomes dense near the outer peripheral end part of the printedwiring board substrate X, and the plating layer becomes thick thereat.In addition, even at parts other than the outer peripheral end part ofthe printed wiring board substrate X, the current distribution becomessparse at parts where the exposed seed layer is densely provided, andthe current distribution becomes dense at parts where the exposed seedlayer is sparsely provided, to thereby generate inconsistencies in theplated layer thickness. Further, depending on individuality based on thespecific configuration or the like of the apparatus, it may be difficultto obtain a uniform current distribution. The shield plate 9 and theanode shield plate 19 are arranged to make uniform the currentdistribution that may become sparse or dense. In other words, it ispossible to uniformly deposit the plated layer by arranging the shieldplate 9 and the anode shield plate 19. Moreover, “the shield anode plate19 that overlaps the shield plate 9 in the front view from the printedwiring board substrate X” referred above includes a state where theanode 6 is concealed by the anode shield plate 19 in the front view fromthe printed wiring board substrate X when the external size of the anodeshield plate 19 is larger than the external size of the anode 6, and astate where the anode shield plate 19 falls within a range of the anode6 in the front view from the printed wiring board substrate X when theexternal size of the anode shield plate 19 is the same as or smallerthan the external size of the anode 6.

The position where the anode shield plate 19 is arranged is notparticularly limited, as long as the position is between the shieldplate 9 and the anode 6, and the anode shield plate 19 does not makecontact with the shield plate 9 and the anode 6. A lower limit value ofthe distance of the anode shield plate 19 from the printed wiring boardsubstrate X may be 100 mm, and preferably 125 mm. An upper limit valueof the distance may be 300 mm, and preferably 250 mm. When the distancedoes not reach the lower limit, it may become difficult to uniformlydeposit the plated layer on the printed wiring board substrate X. Whenthe distance exceeds the upper limit, it may become difficult to controlthe plated layer thickness deposited on the printed wiring boardsubstrate X. “The distance of the anode shield plate 19 from the printedwiring board substrate X” refers to the distance between the center ofthe printed wiring board substrate X having the exposed seed layer, anda center of the anode shield plate 19.

An external size of the anode shield plate 19 that is formed to therectangular shape as illustrated in FIG. 6 is not particularly limited,but a lower limit value of the length along the up and down directionmay be 300 mm, and preferably 550 mm. An upper limit value of the lengthalong the up and down direction may be 1100 mm, and preferably 850 mm. Alower limit value of the length along the horizontal direction may be400 mm, and preferably 500 mm. An upper limit value of the length alongthe horizontal direction may be 1100 mm, and preferably 800 mm.

In addition, the anode shield plate 19 preferably includes anode shieldplate openings 20, as illustrated in FIG. 7 . Because the anode shieldplate 19 includes the anode shield plate openings 20, it is possible topartially validate and invalidate the current generated from the anode6, and more precisely control the current distribution. In addition, thearea of the anode shield plate 19, including the anode shield plateopenings 20, is preferably greater than the area of the anode 6 immersedin the plating solution. When the area of the anode shield plate 19,including the anode shield plate openings 20, is greater than the areaof the anode 6 immersed in the plating solution, it is possible toeasily control the current distribution near the outer peripheral endpart of the printed wiring board substrate X. The shape and the externalsize of the anode shield plate 19, and the shape, size, number, or thelike of the anode shield plate openings 20, may be selected to becomeoptimum, as appropriate, according to the individuality based on thespecific configuration or the like of the plating apparatus 1, theshape, the external size, and the output of the anode 6, the size of theprinted wiring board substrate X, or the like.

[Advantages]

By using the plating apparatus 1 that is provided with the anode shieldplate 19 together with the shield plate 9 in the plating process, thisprinted wiring board production method can more appropriately controlthe current distribution within the plating solution Y. A goodworkability can be obtained by setting the distance between the printedwiring board substrate X and the shield plate 9 to 50 mm or greater and150 mm or less, and the plated layer having a more uniform thickness canbe deposited on the exposed seed layer of the printed wiring boardsubstrate X by providing the anode shield plate 19. Accordingly, it ispossible to improve the production efficiency of the printed wiringboard having the refined conductive pattern that is formed by the platedlayer having the more uniform thickness.

Third Embodiment

<Printed Wiring Board Production Method>

The printed wiring board production method according to still anotherembodiment of the present invention will be described, by referring toFIG. 8 . In this embodiment, constituent parts that are the same asthose of the first embodiment will be designated by the same referencenumerals, and a description thereof will be omitted.

The plating process of this printed wiring board production method usesa plating apparatus 21 to deposit the plated layer on the exposed seedlayer on both surfaces of the printed wiring board substrate X formingthe cathode.

The plating apparatus 21 used by the plating process includes theplating solution Y, the plating solution storage tank 2, and the voltageapplying mechanism 7. A pair of anodes 6 is arranged to oppose eachother near both sidewalls within the plating solution storage tank 2,and a cathode bus bar 22 is provided at an approximate center betweenthe anodes 6. The cathode bus bar 22 holds a substrate fixing jig 23that fixes the printed wiring board substrate X, and the exposed seedlayer of the printed wiring board substrate X forms the cathode. Theshield plate 9 is provided between the cathode bus bar 22 and each ofthe pair of anodes 6. The 2 shield plates 9 are respectively arranged ata distance of 50 mm or greater and 150 mm or less from the front surfaceand the rear surface of the printed wiring board substrate X. The pairof anodes 6, the shielding plates 9, and the printed wiring boardsubstrate X are arranged in parallel to overlap each other in a frontview from one of the anodes 6.

When the current from the voltage applying mechanism 7 flows to theprinted wiring board substrate X forming the cathode, via the pair ofanodes 6 and the cathode bus bar 22, the plated layer is deposited onthe exposed seed layer on both surfaces of the printed wiring boardsubstrate X.

[Advantages]

Because the 2 shield plates 9 are respectively arranged at the distanceof 50 mm or greater and 150 mm or less from the front surface and therear surface of the printed wiring board substrate X, this printedwiring board production method can deposit the plated layer having auniform thickness on both surfaces of the printed wiring board substrateX. In addition, in the case of the printed wiring board productionmethod that arranges the shield element adjacent to the printed wiringboard substrate, a spacing between the 2 shield elements inevitablybecomes narrow, and may cause a collision between the substrate fixingjig and the shield element when arranging and replacing the printedwiring board substrate, in which case the operations of arranging andreplacing the printed wiring board substrate may need to be performeddelicately and carefully. Moreover, in order to avoid collision with theshield element during the operations of arranging and replacing theprinted wiring board substrate, the plating apparatus may need to bemodified to enable simple attachment and detachment of the cathode busbar. On the other hand, in the printed wiring board production methodaccording to this embodiment, the spacing between the 2 shield plates 9is large, and the operations of arranging and replacing the printedwiring board substrate X can be performed with extreme ease. Hence, agood workability can be achieved, and a modification or the like of theplating apparatus 21 becomes unnecessary. Accordingly, it is possible toimprove the production efficiency of the printed wiring board having theconductive pattern that is formed by the plated layer having the uniformthickness on both the front surface and the rear surface of thesubstrate.

Fourth Embodiment

<Printed Wiring Board Production Method>

The printed wiring board production method according to a furtherembodiment of the present invention will be described, by referring toFIG. 9 . In this embodiment, constituent parts that are the same asthose of the first embodiment will be designated by the same referencenumerals, and a description thereof will be omitted.

A plating apparatus used by this printed wiring board production methodincludes the plating solution storage tank 2 that stores the platingsolution Y, a fixing jig 24 that fixes the printed wiring boardsubstrate X forming the cathode and immersed in the plating solution Y,the anode 6 arranged to oppose the printed wiring board substrate X andimmersed in the plating solution Y, and the voltage applying mechanism7.

The plating process of this printed wiring board production method usesthe plating apparatus 1 to deposit the plated layer on the outer surfaceof the exposed seed layer of the printed wiring board substrate Xforming the cathode. Because the fixing jig 24 includes a shield member26, in addition to the shield plate 9, this printed wiring boardproduction method can more appropriately control the currentdistribution within the plating solution Y, uniformly reduce the metalions on the outer surface of the seed layer, and further improve theuniformity of the plated layer thickness. The plating process of thisprinted wiring board production method differs from the plating processof the above-mentioned first embodiment, in that the shield member 26 isprovided, and thus, a description will hereinafter be given mainly onthe shield member 26.

(Fixing Jig)

The fixing jig 24 includes a frame 25, and a pair of arms 5 extendingupward from the frame 25, as illustrated in FIG. 10 , and the frame 25includes an opening for accommodating the printed wiring board substrateX, and holds the outer edge of the printed wiring board substrate X.

The frame 25 includes an inner edge and an outer edge forming arectangular frame body, and holds the printed wiring board substrate Xtherein. In other words, the frame 25 holds the printed wiring boardsubstrate X so as to cover the outer periphery of the printed wiringboard substrate X. In addition, the frame 25 includes shield members 26at parts that hold sides of the printed wiring board substrate X. As anexample, the frame 25 that holds the entire outer periphery of theprinted wiring board substrate X will be described, however, the frame25 is not limited to such, and may include a frame that holds two sidesof the printed wiring board substrate X, such as the left and rightsides in FIG. 10 , for example.

[Shield Member]

The shield members 26 are provided at the parts of the frame 25 thathold the sides of the printed wiring board substrate X. The shieldmembers 26 are arranged parallel to the surface of the printed wiringboard substrate X, and overlap predetermined regions at the end partsalong a width direction (horizontal direction in FIG. 10 ) of theprinted wiring board substrate X in a front view from the anode 6 or theshield plate 9. The shield members 26 are provided from one end part tothe other end part along a height direction (vertical direction in FIG.10 ) of the printed wiring board substrate X in the front view from theanode 6 or the shield plate 9. In the plating solution Y, a distributionof the current flowing from the anode 6 to the exposed seed layer of theprinted wiring board substrate X forming the cathode, becomes dense nearthe outer peripheral end part of the printed wiring board substrate X,and the plating layer may become thick thereat. In addition, dependingon individuality based on the specific configuration or the like of theapparatus, it may be difficult to obtain a uniform current distribution.In this printed wiring board production method, the shield plate 9 isarranged and the shield members 26 are provided, to make uniform thecurrent distribution that may become sparse or dense.

In the front view from the anode 6 or the shield plate 9, an area ofregions where the shield member 26 overlaps an end part (first end part)on a first side and an end part (second end part) on a second side ofthe printed wiring board substrate X along the width direction, ispreferably 2% or higher and 30% or lower than the area of the printedwiring board substrate X. In addition, a lower limit value of a ratio ofthe area of the regions where the shield member 26 overlaps the firstend part or the second end part of the printed wiring board substrate X,with respect to the area of the printed wiring board substrate X, ispreferably 1%, more preferably 2.4%, and even more preferably 4.8%. Anupper limit value of the above-mentioned ratio is preferably 15%, morepreferably 11.9%, and even more preferably 8.8%. When the ratio does notreach the lower limit value, the shielding effect may not be exhibited,and it may not be possible to make the plated layer thickness uniform atthe ends along the width direction of the printed wiring board substrateX. When the above-mentioned ratio exceeds the upper limit value, theshielding effect may become excessive, and it may not be possible tomake the plated layer thickness uniform at the end parts along the widthdirection of the printed wiring board substrate X. Further, the area ofthe region where the shield member 26 overlaps the first end part of theprinted wiring board substrate X, and the area of the region where theshield member 26 overlaps the second end part of the printed wiringboard substrate X, are preferably the same.

A distance between the surface of the printed wiring board substrate Xon the side provided with the shield member 26, and a surface of theshield member 26 opposing the surface of the printed wiring boardsubstrate X, is not particularly limited, as long as the shield member26 does not make contact with the shield plate 9 and the surface of theprinted wiring board substrate X, between the shield plate 9 and theprinted wiring board substrate X, but the shield member 26 is preferablyarranged at a distance of 1 mm or greater and 50 mm or less from thesurface of the printed wiring board substrate X. A lower limit value ofthe above-mentioned distance is preferably 2.5 mm, and more preferably 5mm. An upper limit value of the above-mentioned distance is preferably30 mm, and more preferably 15 mm. When the distance does not reach thelower limit value, the shielding effect may become excessive, and it maynot be possible to make the plated layer thickness uniform at the endparts along the width direction of the printed wiring board substrate X.When the distance exceeds the upper limit value, the shielding effectmay not be exhibited, and it may not be possible to make the platedlayer thickness uniform at the end parts along the width direction ofthe printed wiring board substrate X.

The shape of the shield member 26 is not particularly limited, as longas the end regions along the width direction of the printed wiring boardsubstrate X can be covered, and may be a plate shape, for example.

The shield member 26 preferably includes shield member openings 27, asillustrated in FIG. 11 . When the shield member 26 covers the endregions along the width direction of the printed wiring board substrateX, it is possible to reduce the ease with which the current density atthe end parts along the width direction of the printed wiring boardsubstrate X becomes dense, and by including the shield member openings27 in the shield member 26, it becomes possible to precisely control thecurrent distribution, and deposit the plated layer having the uniformthickness on the printed wiring board substrate X.

An opening ratio of the shield member 26 is preferably 20% or higher and80% or lower. By setting the above-mentioned opening ratio in thisrange, it becomes possible to easily and precisely control the currentdistribution. A lower limit value of the opening ratio is preferably30%, and more preferably 40%. An upper limit value of the opening ratiois preferably 70%, and more preferably 60%. When the opening ratio doesnot reach the lower limit value, the effect of controlling the currentdistribution may not be sufficiently exhibited, and it may be difficultto make the plated layer thickness uniform. When the opening ratioexceeds the upper limit value, the shielding effect may deteriorate, andit may not be possible to make the plated layer thickness uniform. Theopening ratio of the shield member refers to a ratio of the area of theshield member openings with respect to the area of the shield member(including the shield member openings).

The shield member openings 27 are not limited to a particular shape, anda circular hole, a rectangular hole, a diamond-shaped hole, or the likemay be used therefor. In addition, the shield member openings 27 havingthe same shape may be arranged at the same spacing, or alternatively,the shield member openings 27 having different shapes may be arranged atarbitrary spacings.

As illustrated in FIG. 12 , a plurality of plate-shaped or boss-shaped(pillar-shaped) shield members 26 may be provided at a constant spacing.In other words, instead of providing the shield member openings 27 inthe shield member 26, the shield members 26 having a predetermined shapemay be provided at the constant spacing, to enable control of thecurrent distribution at the end parts along the width direction of theprinted wiring board substrate X. In this case, the plurality of shieldmembers 26 may have different shapes, instead of having the same shape.In addition, the spacing with which the plurality of shield members 26are provided may be arbitrary, instead of being set constant.

A material used for the shield members 26 is not particularly limited,as long as the material is an insulator that has plating resistance,similar to the shield plate 9, and known materials may be used therefor.

[Advantages]

The plating process of this printed wiring board production method usesthe fixing jig 24 having the shield members 26, in the plating apparatus1 provided with the shield plate 9, and thus, it is possible to moreappropriately control the current distribution within the platingsolution Y. Generally, when a positional error is generated along thewidth direction of the printed wiring board substrate X, that is, whenthe plating process is performed in a state where one side of theprinted wiring board substrate X is arranged close to one sidewall ofthe plating solution storage tank 2, and the other side of the printedwiring board substrate X is arranged distant from the other sidewall ofthe plating solution storage tank 2, the current distribution becomesdistorted near the end parts along the width direction of the printedwiring board substrate X, and the plated layer thickness easily becomesinconsistent. But because the shield members 26 are provided inpredetermined regions at the end parts along the width direction of theprinted wiring board substrate X, this printed wiring board productionmethod can reduce the distortion of the current distribution near theend parts along the width direction of the printed wiring boardsubstrate X, even when the positional error is generated along the widthdirection of the printed wiring board substrate X, and it is thuspossible to deposit the plated layer having a more uniform thickness onthe exposed seed layer of the printed wiring board substrate X.Accordingly, it is possible to improve the production efficiency of theprinted wiring board having the refined conductive pattern that isformed by the plated layer having the more uniform thickness.

Other Embodiments

The present invention is not limited to the examples of embodimentsdisclosed above. The scope of the present invention is not limited thestructure of the above-mentioned embodiments, and is intended to includeall modifications within the meaning and scope of the claims presentedand equivalents thereof.

The plating process of the printed wiring board production methodaccording to the third embodiment described above arranges the printedwiring board substrate at the approximate center of the plating solutionstorage tank, and the arranges the pair of anodes so that the printedwiring board substrate is sandwiched between the pair of anodes.However, a different plating process of the printed wiring boardproduction method, that arranges the anode at the approximate center ofthe plating solution storage tank, arranges a pair of printed wiringboard substrates so that the anode is sandwiched between the pair ofprinted wiring board substrates, and simultaneously deposits the platedlayer on one surface of each of the printed wiring board substrates,also falls within the scope of the present invention.

In addition, although the plating process of the printed wiring boardproduction method described above uses the shield plate and the anodeshield plate, it is also within the scope of the present invention tofurther use one or two or more shield plates. For example, the shieldplate may be divided into a plurality of plates, and these plates may bearranged in parallel between the anode and the printed wiring boardsubstrate, or the like.

Further, in the described printed wiring board production method, theexample of the fixing jig includes the shield members extending from theupper end to the lower end of the printed wiring board substrate at theend regions along the width direction of the printed wiring boardsubstrate, however, the present invention is not limited to thisexample. It is within the scope of the present invention to provide theshield member at a part of the end region along the width direction ofthe printed wiring board substrate, and to provide the shield member ofthe fixing jig at a part or an entirety of the end region along avertical (perpendicular) direction of the printed wiring boardsubstrate.

The printed wiring board substrate used in the plating process of theprinted wiring board production method is not limited to a printedwiring board substrate from which 1 printed wiring board is obtained,but may be a printed wiring board substrate from which 2 or more printedwiring boards are obtained.

In a case where the plated solution storage tank accommodates aplurality of printed wiring board substrates, or is provided with aplurality of anodes, the voltage applying mechanism may be configured asa voltage applying mechanism that includes a plurality of powersupplies.

What is claimed is:
 1. A printed wiring board production method thatfoiiiis a conductive pattern on a base film by an additive method or asubtractive method, comprising: a plating process that electroplates theconductive pattern on a surface of the base film, wherein the platingprocess includes a shield plate arranging process that arranges a shieldplate between an anode and a printed wiring board substrate that forms acathode, a substrate arranging process that arranges the printed wiringboard substrate in a plating tank by a jig that holds the printed wiringboard substrate, and an anode shield plate arranging process thatarranges an anode shield plate between the shield plate and the anode ata position separated from the shield plate and the anode, a distancebetween the shield plate and the printed wiring board substrate is 50 mmor greater but 150 mm or less, a distance between the anode shield plateand the printed wiring board substrate is 100 mm or greater but 300 mmor less, the shield plate includes an opening region opposing theprinted wiring board substrate in a plan view, and shield plate openingsformed in an array within the opening region, the opening regionincludes a rectangular central region at a center portion of the openingregion, and a pair of rectangular end regions at end portions onopposite sides of the central region, the rectangular central regiondoes not overlap the pair of rectangular end regions in the plan view,and an opening ratio of the rectangular central region of the openingregion is different from an opening ratio of each of the pair ofrectangular end regions of the opening region.
 2. The printed wiringboard production method as claimed in claim 1, wherein the jig includesa shield member.
 3. The printed wiring board production method asclaimed in claim 2, wherein the shield member is arranged at least in anend region along a width direction of the printed wiring board substratein a plan view.
 4. The printed wiring board production method as claimedin claim 2, wherein the shield member includes shield member openings.5. The printed wiring board production method as claimed in claim 4,wherein an opening ratio of the shield member is 20% or higher but 80%or lower.
 6. The printed wiring board production method as claimed inclaim 1, wherein the opening ratio of the rectangular central region ofthe opening region is 10% or higher but 50% or lower, and the openingratio of each of the pair of rectangular end regions of the openingregion is higher than the opening ratio of the rectangular centralregion.
 7. The printed wiring board production method as claimed inclaim 1, wherein an external size of the shield plate is larger than anexternal size of the printed wiring board substrate in a plan view. 8.The printed wiring board production method as claimed in claim 1,wherein the anode shield plate includes a plurality of anode shieldplate openings.
 9. The printed wiring board production method as claimedin claim 1, wherein an area of the anode shield plate is larger than animmersion area of the anode into a plating solution during the platingprocess.
 10. The printed wiring board production method as claimed inclaim 1, wherein a thickness of a plated layer formed as the conductivepattern is 30 μm or greater, and an inconsistency of the thickness iswithin 15% of an average thickness of the plated layer.
 11. The printedwiring board production method as claimed in claim 1, wherein theconductive pattern is formed by a semi-additive method.
 12. The printedwiring board production method as claimed in claim 1, wherein the shieldplate, in a front view of the anode, includes a frame shaped regionhaving an external size exceeding an external size of the printedcircuit board substrate, the central region, located at a center on. aninner side of the frame shaped region, and the pair of rectangular endregions located at an upper end and a lower end of the rectangularcentral region, respectively, on the inner side of the frame shapedregion, and the frame shaped region completely surrounds the rectangularcentral region and the pair of rectangular end regions in the plan view.13. The printed wiring board production method as claimed in claim 12,wherein the opening ratio of the rectangular central region of theopening region is 10% or higher hut 50% or lower, and the opening ratioof each of the pair of rectangular end regions of the opening region is101% or higher hut 110% or lower.